1. Field of the Invention
The present invention relates to a color photographic process and, in particular, to a color photographic process giving high sensitivity, contrast, and maximum density, as well as less fog, under rapid processing condition. More particularly, the invention relates to a color photographic process wherein silver images and dye images obtained by color development are used as color photographic images.
2. Description of the Prior Art
In photographic processing for obtaining color photographic images by processing silver halide color photographic materials, it is well known to obtain color photographic images by forming dyes by the imagewise coupling of an oxidized aromatic primary amine developer and dye-forming couplers. Also, a color photographic process wherein color photographic images composed of dyes and silver are formed by processing coupler-containing photographic materials using the steps of color development, fixing, washing, and drying, without employing a silver removal process, is known, as disclosed in U.S. Pat. Nos. 3,622,626, 3,627,530, 3,734,735, and 3,809,906, British Pat. No. 1,122,085, West German Patent Application (OLS) No. 1,158,836 and Japanese Patent Application (OPI) No. 37539/72 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application").
Color photographic materials using images composed of dyes and silver have advantages, in that the amount of imaged information is large, owing to high discrimination and good granularity, and the amount of silver halide contained in the photographic materials may be reduced, and therefore this photographic technique for color photographic materials is effectively applied to radiographic materials (requiring a large amount of silver halide), photosensitive materials for making printing plates, and so forth.
Considering the purposes of radiographic materials, photosensitive materials for making printing plates, etc., these materials are not required to form multicolored photographic images, and may be monochromic color photographic materials. Desirably they are photographic materials forming black images.
These photographic materials are usually processed by rapid processing and a rapid process using an automatic processor has been widely employed. Very rapid processing is particularly required for radiographic materials, for the purpose of interpretation and use of the X-ray image as soon as possible, and it is now common to finish the total processing steps of development, fixing, washing, and drying within 2 minutes for black and white radiographic materials.
Therefore, color radiographic materials should be able to be processed rapidly also, as in the case of black and white radiographic materials.
Various attempts have been proposed for increasing the processing speed of color development, and of these attempts, a process of performing color development in the presence of an aromatic primary amino color developing agent, a hydroxylamine derivative, and a 1-aryl-3-pyrazolidone derivative having two substituents at the 4-position disclosed in U.S. Pat. No. 4,155,763 is effective.
In rapid processing, it is of course necessary that the process steps other than development also be conducted rapidly. That is, it is also required to rapidly conduct the other steps of fixing, washing, and drying. To increase the processing speed for the fixing and washing steps, the use of an acid hardening fix solution as described in U.S. Pat. No. 3,994,729 is effective.
It is, however, known that when photographic materials are processed by an acid hardening fix solution after the formation of dyes and silver images using a color developer, a part of the dye formed in the color development step is destroyed.
The occurrence of such a phenomenon can be prevented by using an alkaline fix solution as the fixing solution, as is described in Japanese Patent Application (OPI) No. 99522/76.
However, when an alkaline fix solution is used in the fixing step, the gelatin in the photographic material is swelled very greatly, and the gelatin-containing layers absorb a large amount of water in the washing step, thereby the burden of drying the photographic materials becomes that large it becomes impossible to dry the photographic materials to the necessary level using an ordinary high speed automatic processor.
Thus, in the case of rapid processing of a color photographic material containing at least one kind of color-forming coupler, including the steps of development, fixing, washing and drying, it is necessary, to obtain a completely dried photographic film, to use an acid hardening fix solution as the fix solution. However, the use of an acid hardening fix solution is undesirable in that a part of the dye formed in the development step is destroyed in the fixing step, thereby reducing the photographic sensitivity, contrast, and maximum density. Also, it has been confirmed that silver of the images formed by the development takes part in the destruction of the dyes. Therefore, the extent of the destruction of the dyes becomes larger at portions of the image having high image density. Therefore, the image density at high density portions which are particularly important in the case of color radiographic materials, is adversely affected by the above-mentioned phenomenon. Hence, it is important to overcome such problems in the art as have been described above.